staging: rtl8723bs: fix remote heap info disclosure and OOB reads

PATCH Superseded [email protected] 2 participants 2 messages May 14 – May 21

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2026-05-14 09:05 UTC #0 lore raw

PATCH v6 1/1 staging: rtl8723bs: fix remote heap info disclosure and OOB reads

From: Luka Gejak <[email protected]>

When building an association request frame, the driver iterates over the ies received from the ap. In three places, the driver trusts the attacker-controlled pIE->length without validating that it meets the minimum expected size for the respective ie.

For WLAN_EID_HT_CAPABILITY, this causes an oob read of adjacent heap memory which is then transmitted over the air (remote heap information disclosure). For WLAN_EID_VENDOR_SPECIFIC, it causes two separate oob
reads: one when checking the 4-byte oui, and another when copying the 14-byte wps ie.

Fix these issues by adding upper-bound checks at the start of the loop to ensure the ie fits within the buffer, and explicit lower-bound checks to return a failure if the length is insufficient. For HT_CAPABILITY, also clamp the length passed to rtw_set_ie() to the struct size.

Fixes 554c0a3abf21 ("staging: Add rtl8723bs sdio wifi driver")

Cc [email protected]

Signed-off-by Luka Gejak <[email protected]>

---
Changes in v6:
- Restore full changes history.

Changes in v5:
- Address sashiko comments.

Changes in v4:
- Added upper-bound checks at the start of the loop to ensure the ie fits within the received buffer, as pointed out by Dan.
- Updated commit message to reflect the addition of upper-bound checks.

Changes in v3:
- Switched to fail-fast handling for malformed IEs in issue_assocreq().
- Fixed HT capability path to use structure-sized output length in rtw_set_ie().
- Updated commit message to reflect all oob read cases.

Changes in v2:
- Refactored rtw_set_ie() alignment to follow "open parenthesis" style.
- Allowed the line length to exceed 100 characters for better readability as requested by Greg KH.

 drivers/staging/rtl8723bs/core/rtw_mlme_ext.c | 32 ++++++++++++++++++-
 .../staging/rtl8723bs/core/rtw_wlan_util.c    |  6 ++++
 2 files changed, 37 insertions(+), 1 deletion(-)

drivers/staging/rtl8723bs/core/rtw_mlme_ext.c +31 -1

index cfd3eb253350..e448a814eb1c 100644
@@ -2862,6 +2862,9 @@ void issue_assocreq(struct adapter *padapter)
 		if (pmlmeinfo->network.supported_rates[i] == 0)
 			break;
 
+		if (index >= NumRates)
+			break;
+
 		/*  Check if the AP's supported rates are also supported by STA. */
 		for (j = 0; j < sta_bssrate_len; j++) {
 			 /*  Avoid the proprietary data rate (22Mbps) of Handlink WSG-4000 AP */

@@ -2891,10 +2894,25 @@ void issue_assocreq(struct adapter *padapter)
 
 	/* vendor specific IE, such as WPA, WMM, WPS */
 	for (i = sizeof(struct ndis_802_11_fix_ie); i < pmlmeinfo->network.ie_length;) {
+		if (i + 2 > pmlmeinfo->network.ie_length) {
+			rtw_free_xmitbuf(pxmitpriv, pmgntframe->pxmitbuf);
+			rtw_free_xmitframe(pxmitpriv, pmgntframe);
+			goto exit;
+		}
+
 		pIE = (struct ndis_80211_var_ie *)(pmlmeinfo->network.ies + i);
 
+		if (pIE->length > pmlmeinfo->network.ie_length - i - 2) {
+			rtw_free_xmitbuf(pxmitpriv, pmgntframe->pxmitbuf);
+			rtw_free_xmitframe(pxmitpriv, pmgntframe);
+			goto exit;
+		}
+
 		switch (pIE->element_id) {
 		case WLAN_EID_VENDOR_SPECIFIC:
+			if (pIE->length < 4)
+				goto exit;
+
 			if ((!memcmp(pIE->data, RTW_WPA_OUI, 4)) ||
 					(!memcmp(pIE->data, WMM_OUI, 4)) ||
 					(!memcmp(pIE->data, WPS_OUI, 4))) {

@@ -2906,6 +2924,9 @@ void issue_assocreq(struct adapter *padapter)
 					 * extensions information to AP
 					 */
 
+					if (pIE->length < 14)
+						goto exit;
+
 					vs_ie_length = 14;
 				}

@@ -2919,8 +2940,17 @@ void issue_assocreq(struct adapter *padapter)
 		case WLAN_EID_HT_CAPABILITY:
 			if (padapter->mlmepriv.htpriv.ht_option) {
 				if (!(is_ap_in_tkip(padapter))) {
+					if (pIE->length < sizeof(struct HT_caps_element)) {
+						rtw_free_xmitbuf(pxmitpriv, pmgntframe->pxmitbuf);
+						rtw_free_xmitframe(pxmitpriv, pmgntframe);
+						goto exit;
+					}
+
 					memcpy(&(pmlmeinfo->HT_caps), pIE->data, sizeof(struct HT_caps_element));
-					pframe = rtw_set_ie(pframe, WLAN_EID_HT_CAPABILITY, pIE->length, (u8 *)(&(pmlmeinfo->HT_caps)), &(pattrib->pktlen));
+					pframe = rtw_set_ie(pframe, WLAN_EID_HT_CAPABILITY,
+							    sizeof(struct HT_caps_element),
+							    (u8 *)&pmlmeinfo->HT_caps,
+							    &pattrib->pktlen);
 				}
 			}
 			break;

drivers/staging/rtl8723bs/core/rtw_wlan_util.c +6 -0

index cc1a7497764c..dc4abef3a7b8 100644
@@ -1327,8 +1327,14 @@ unsigned int is_ap_in_tkip(struct adapter *padapter)
 
 	if (rtw_get_capability((struct wlan_bssid_ex *)cur_network) & WLAN_CAPABILITY_PRIVACY) {
 		for (i = sizeof(struct ndis_802_11_fix_ie); i < pmlmeinfo->network.ie_length;) {
+			if (i + 2 > pmlmeinfo->network.ie_length)
+				return false;
+
 			pIE = (struct ndis_80211_var_ie *)(pmlmeinfo->network.ies + i);
 
+			if (pIE->length > pmlmeinfo->network.ie_length - i - 2)
+				return false;
+
 			switch (pIE->element_id) {
 			case WLAN_EID_VENDOR_SPECIFIC:
 				if ((!memcmp(pIE->data, RTW_WPA_OUI, 4)) && (!memcmp((pIE->data + 12), WPA_TKIP_CIPHER, 4)))

Signature · 1 line

2.54.0

Greg Kroah-Hartman

maintainer

2026-05-21 09:22 UTC #1 lore raw

Quoted 19 lines · On Thu, May 14, 2026 at 11:05:25AM +0200, [email protected] wrote:

From: Luka Gejak <[email protected]>
When building an association request frame, the driver iterates over the ies received from the ap. In three places, the driver trusts the attacker-controlled pIE->length without validating that it meets the minimum expected size for the respective ie.
For WLAN_EID_HT_CAPABILITY, this causes an oob read of adjacent heap memory which is then transmitted over the air (remote heap information disclosure). For WLAN_EID_VENDOR_SPECIFIC, it causes two separate oob
reads: one when checking the 4-byte oui, and another when copying the 14-byte wps ie.
Fix these issues by adding upper-bound checks at the start of the loop to ensure the ie fits within the buffer, and explicit lower-bound checks to return a failure if the length is insufficient. For HT_CAPABILITY, also clamp the length passed to rtw_set_ie() to the struct size.

Quoted 3 lines

Fixes 554c0a3abf21 ("staging: Add rtl8723bs sdio wifi driver")
Cc [email protected]
Signed-off-by Luka Gejak <[email protected]>

More comments:

	https://sashiko.dev/#/patchset/[email protected]